All categories

3 years ago

Reena is making a video from the pictures she took during her first vacation with family. She wants

Chemistry

1 answer:

KonstantinChe [14]3 years ago

7 0

she will have to listen to all of carefully while she is writing for example:

she will listen and look at her writing page (where she writes) she looks while she listens and writes what she hears for example again:

(pretend as i am her.)

"Hey mom, dad, brother come i see crabs!" as she writes it she focuses on how she writes and stops the video and back up again to listen so she can see if it was correct.

You might be interested in

Choose all of the options that demonstrate how humans are impacting the water cycle.

Fantom [35]

Answer:

A.) Air pollutants wash onto land and water bodies from precipitation

C.) Storm water runoff carries pollution

I hope I helped! ^-^

5 0

2 years ago

A sample of paper from an ancient scroll was found to contain 39.5% 14C content as compared to a present-day sample. The t1/2 fo

nirvana33 [79]

Answer

7665 years

Procedure

Let N₀ be the amount of carbon-14 present in a living organism. According to the radioactive decay law, the number of carbon-14 atoms, N, left in a dead tissue sample after a certain time, t, is given by the exponential equation:

N = N₀e^(-λt)

where λ is the decay constant which is related to half-life (T1/2) by the equation:

$\lambda=\frac{ln(2)}{t_{\frac{1}{2}}}$

Here, ln(2) is the natural logarithm of 2.

The percent of carbon-14 remaining after time t is given by N/N₀.

Using the first equation, we can determine λt.

The half-life of carbon-14 is 5,720 years, thus, we can calculate λ using the second equation, and then find t.

$\lambda=\frac{ln(2)}{5720}=1.211\times10^{-4}$

Solving the second equation for t, and using the λ we have just calculated we will have

t= 7665 years

3 0

1 year ago

What is an example of conduction?

pickupchik [31]

Answer:

The correct answer is A.

5 0

3 years ago

Read 2 more answers

6. How many moles of water would require 92.048 kJ of heat to raise its temperature from 34.0 °C to 100.0 °C? (3 marks)

scoray [572]

Taking into account the definition of calorimetry, 0.0185 moles of water are required.

<h3>Calorimetry</h3>

Calorimetry is the measurement and calculation of the amounts of heat exchanged by a body or a system.

Sensible heat is defined as the amount of heat that a body absorbs or releases without any changes in its physical state (phase change).

So, the equation that allows to calculate heat exchanges is:

Q = c× m× ΔT

where Q is the heat exchanged by a body of mass m, made up of a specific heat substance c and where ΔT is the temperature variation.

<h3>Mass of water required</h3>

In this case, you know:

Heat= 92.048 kJ
Mass of water = ?
Initial temperature of water= 34 ºC
Final temperature of water= 100 ºC
Specific heat of water = 4.186 $\frac{J}{gC}$

Replacing in the expression to calculate heat exchanges:

92.048 kJ = 4.186 $\frac{J}{gC}$ × m× (100 °C -34 °C)

92.048 kJ = 4.186 $\frac{J}{gC}$ × m× 66 °C

m= 92.048 kJ ÷ (4.186 $\frac{J}{gC}$ × 66 °C)

<u><em>m= 0.333 grams</em></u>

<h3>Moles of water required</h3>

Being the molar mass of water 18 $\frac{g}{mole}$ , that is, the amount of mass that a substance contains in one mole, the moles of water required can be calculated as:

$amount of moles=0.333 gramsx\frac{1 mole}{18 grams}$

<u><em>amount of moles= 0.0185 moles</em></u>

Finally, 0.0185 moles of water are required.

Learn more about calorimetry:

brainly.com/question/11586486?referrer=searchResults

brainly.com/question/24724338?referrer=searchResults

brainly.com/question/14057615?referrer=searchResults

brainly.com/question/24988785?referrer=searchResults

brainly.com/question/21315372?referrer=searchResults

brainly.com/question/13959344?referrer=searchResults

brainly.com/question/14309811?referrer=searchResults

brainly.com/question/23578297?referrer=searchResults

8 0

2 years ago

PLZ HELP WITH THESE QUICK// WILL AWARD BRANLIEST

Tom [10]

Answer 1

The sample will dissolve in more than 1 minute.

Explanation :-

Generally Solubility and rate of solubility of substances increase with the increase in temperature. So lower the temperature less fast will it dissolve in the same amount of water.

Since at 50 C it takes 1 minute to dissolve, at 20 C which is lower temperature it will take more time to dissolve.

Answer 2

Transition metals

Explanation:-

Hardness depends on the extent of metallic bonding for metals. More the number of electrons more the metallic bonding.

Alkali metals with just 1 valence electron have weak metallic bonding. Alkaline earth metals have just 2 valence electrons. Transition elements has more electrons in penultimate shell and valence shell than lanthanides. Transition metals with most metallic bonding are the hardest

5 0

3 years ago